An increased awareness of the nutritional status of patients undergoing major elective surgery has lead to the finding that certain measurements of nutritional status either alone (dynamometry) or in combination (Prognostic Nutritional Index or the 'Sheffield' modified index) can identify patients at high risk from developing complications. This study presents a comparison of forearm muscle dynamometry versus the 'Sheffield' index in 70 patients undergoing major elective abdominal and urological surgery. Both tests successfully identified patients at risk of major post operative complications and death, but they failed to predict those patients who developed minor post operative complications. These data suggest that only major postoperative complications relate to the pre-operative nutritional status of patients undergoing major elective surgery. Identification of a patient as being at high risk of developing major postoperative complications by dynamometry or the 'Sheffield' index should alert the surgeon to the possible requirement for perioperative nutritional support.